The present invention relates to a covered railway hopper car.
In the past, covered hopper cars have been of two general forms. One such form of car has been constructed of substantially vertical flat side walls. Such flat sided cars have had the disadvantage that, although the volumetric capacity of the car is maximized due to their flatness, reinforcing side posts as well as end structures of considerable weight and complexity are necessary to reinforce the side walls and to transmit the forces encountered by the car to the roof of the car, respectively. This is due to the fact that a flat side walled car is essentially the weakest form from a structural standpoint and, without such support members, it is unable to withstand the loads imposed on the car walls by the lading and during transit. Moreover, such flat side walled cars are generally incapable of pressure or vacuum unloading due to the substantial pressure differentials which are experienced. Indeed, where external vertical support posts have been provided in such flat walled cars, the volumetric capacity increase which might otherwise be realized in such cars is lost due to the need for positioning the flat side walls within the maximum dimensional tolerances required by prevailing railway standards in order to accommodate the thickness of the external vertical supports.
In order to overcome some of these disadvantages of the flat side walled hopper cars, the second form of such car was developed. These are cars which have arcuate side walls. The arcuate side walled cars overcame some of the above-mentioned disadvantages in varying degree. Where the arcuate curvature of the side walls was only sufficiently arcuate, i.e. of substantially large radius, to overcome the need for the side vertical posts necessary in the flat walled cars, the capacity of the cars was increased by elimination of the support posts. However, end support structures of substantial weight and detail were still necessary to distribute the forces encountered by the car. Moreover, even though these hopper cars with large radii of curvature overcame the need for external support posts, they still did not possess sufficient strength to allow for unloading techniques other than simple gravity unloading, i.e. they were incapable of withstanding the substantial pressure differentials encountered in vacuum or pneumatic unloading. If the degree of curvature in these prior arcuate side walled cars was increased by an amount sufficient to enable elimination of end support structures of substantial weight and comlexity and/or to provide for vacuum or pressure unloading, the degree of curvature, i.e. the radius of curvature, had to be shortened to such extent that substantial volumetric capacity of the car was sacrificed.
In the covered hopper car of the present invention, each of the several above-mentioned disadvantages has been avoided and, yet, the volume of the car has been maximized, the weight of the car has been minimized and the cost and ease of assembly and production of the car has been improved. In a car incorporating the principles of the present invention, an end structure has been incorporated into the car which is substantially simpler, lighter and less expensive than the prior end structures, but just as or more effectively distributes the forces exerted on the car directly to the roof of the car. In a hopper car incorporating the principles of the present invention, substantial and additional reinforcement of the side walls of the car over its longitudinal length is realized, allowing the maximum radius of curvature of the arcuate side walls of such car and maximum capacity of the car and, even though the capacity of the car is maximized, either gravity, pneumatic or vacuum unloading techniques may be employed. Moreover, unloading of the covered hopper car incorporating the principles of the present invention is improved over the prior arcuate side walled cars, whatever method of unloading is employed.
In one principal aspect of the present invention, a covered railway hopper car comprises side walls each of which includes a first arcuate sheet portion which extends longitudinally of the car and which has upper and lower boundaries, and a second side sheet portion, which defines the bottom of the side walls, and which also extends longitudinally of the car and is substantially flatter in cross section than the first arcuate side sheet portion. The second side sheet portion also has upper and lower boundaries and is positioned beneath and secured adjacent its upper boundary to the first arcuate side sheet portion adjacent the lower boundary of the latter. A roof covers the car and is secured to the first arcuate side sheet portion adjacent its upper boundary, and a reinforcing member extends longitudinally of the car and reinforces at least one of these side sheet portions.
In another principal aspect of the present invention in the covered hopper car just described, the reinforcing member includes a longitudinally, continuously extending longeron intermediate the upper and lower boundaries of the said sheet portions. This longeron is secured to the side sheet portions at a location adjacent the location at which the side sheet portions are respectively secured to each other. The reinforcing member also includes a side sill which extends substantially continuously and longitudinally over the length of the car and is secured to the second side sheet portion between its upper and lower boundaries to further reinforce the car.
In still another principal aspect of the present invention, an improved end support structure for a covered railway hopper car includes a first vertical support which extends vertically between and which is secured to the shear plate of the car and the end slope wall in a plane located intermediate the top of the end slope wall and the location where the plane of the horizontal shear plate intersects the end slope wall. A second vertical support extends upwardly adjacent that vertical plane between the end slope sheet and the roof of the car to transmit forces substantially in that vertical plane directly to the roof at a location spaced from the vertical end wall.
These and other objects, features and advantages of the present invention will be more clearly understood through a consideration of the following detailed description.